California cops are struggling to crack one of the biggest cases they’ve ever seen — the theft of 140,000 pounds of walnuts, officials said Thursday.

Thieves broke down fences surrounding the GoldRiver Orchards storage facility in Escalon, Calif., and drove off with three double-trailers filled with out-of-shell walnut meat, authorities said.

The wholesale value of those stolen nuts — swiped over the weekend — is about $370,000, according to San Joaquin County Sheriff’s deputy Les Garcia. But officials at the California Walnut Board place the value at closer to $600,000.

Previous walnut thefts have been in the hundreds and occasionally thousands of pounds — never anything close to 140,000 pounds, according to Carl Eidsath, technical support director for the California Walnut Board.

“This [theft] really knocks of out of the park,” said Eidsath. “They’re [GoldRiver Orchard] dumbfounded. They had a really good fence surrounding that thing but they [thieves] just broke it down. They’re [orchard owners] just flabbergasted.”

Eidsath said it’s likely thieves have squirreled away their loot with plans to ship it to Turkey or China, the biggest overseas walnut consumers.

“We’ve seen a level of sophistication with these guys,” Eidsath said. “They’re not going to be setting up shop selling this along [Interstate] 99.”